For the word of God is living and active, and sharper than any two-edged sword, piercing even to the dividing of soul and spirit, of both joints and marrow, and is able to discern the thoughts and intentions of the heart.–Hebrews 4:12
And take the helmet of salvation, and the sword of the Spirit, which is the word of God;–Ephesians 6:17
He had seven stars in his right hand. Out of his mouth proceeded a sharp two-edged sword. His face was like the sun shining at its brightest.–Revelation 1:16
Often I hear the sword being referenced as the device to slay unbelievers or sinners. However, as noted in the above verses, the sword is God’s word. God’s word penetrates, like a sword, to get to our interior.
In Matthew 23 as well as other places in the gospels, Jesus uses some very harsh words to penetrate the wall of tradition, rules, and self-righteousness the Pharisees had erected around their hearts. This wasn’t because Jesus hated them, but it seems only the truth spoken in love could penetrate their callous exterior.